965052 - [B2G][RTSP]Audio track gradually falls behind video.

Status: RESOLVED WONTFIX

(Core :: Audio/Video, defect)

Description

[Ross Kuhlman ([e-mail])]

Attachment: AudioLagsBehind.txt

Device is playing a rtsp video on the browser. The audio track slowly falls behind the video. About five minutes into a video, the sound is around half a second behind the video. If the user pauses the video, the sound will be back in sync after the video is resumed.

Repro Steps:
1) Updated Buri to BuildID: 20140127004002
2) Launch Browser app and navigate to http://bit.ly/1bsSLUz.
3) Use the search bar to find a video that is at least 5 minutes in length. (I searched for 'fail')
4) Watch the video for several minutes.

Actual:
Audio track starts to noticeably lag behind the video.

Expected:
The audio and video remain in sync for the duration of the video.

Environmental Variables:
Device: Buri v1.3 Moz RIL
BuildID: 20140127004002
Gaia: 25a45a836a4a21a30f63fa7b544b42e8b781180a
Gecko: c40099a42c1f
Version: 28.0a2
Firmware Version: v1.2-device.cfg

Notes:
* Workaround: pausing and resuming the video will sync the audio track to the video.

Repro frequency: 100%
See attached: logcat

Comment 1

[Jason Smith [:jsmith]]

We can't ever end up in a situation where audio & video tracks fall out of sync - it ruins the user experience of playing videos on the web.

Comment 2

[Ken Chang[:kenkai]]

It blocks 1.4 feature.

Comment 3

[Vincent Chang[:vchang][changyihsin]]

We just try the same rtsp url in PC using vlc and Android phone, and found the same behavior. We think the problem should be the media source in Youtube.